* move save_op to fluid

* fix namespace

* move_load_kernel

* fix kernel_register

* move serialization to fluid

* fix test

* fix bugs

* execute use kernel_key first

* change OpKernelType->KernelKey

* fix py3 compile error, remove redundant header files

* fix build_strategy_test

* fix DataType::RAW

* fix custom_type test: operator_test.cc

* fix transform place

* fix backends_are_same_class

* try fix place TransDataDevice

* support all KernelKey

* fix TransformData

* fix place_are_same_class

* fix merge

* fix test_params_no_grad

* fix specific place of GetExpectedKernelType

* fix specific place of GetExpectedKernelType

* fix GetKernelTypeForVar

* fix dtype error

* fix fetch_v2

* change GetKernelTypeForVar

* fix interpreter

* fix typo error

* polish codes

* polish codes

* polish codes

* fix conflict

* replace LoDTensor with phi::DenseTensor in fluid\operators

* replace LoDTensor with phi::DenseTensor in fluid\operators

* Update split_lod_tensor_op.cc

* Update warpctc_op.cc

* Update broadcast_tensors_op.cc

* Update crf_decoding_op.cc

* Update lstm_op.cc

* Update lstm_op.cc

* Update lod_reset_op.cc

* Update gru_op.cc

* Update linear_chain_crf_op.cc

* resume 2 files for confilct

* Update gru_op.cc

* Update linear_chain_crf_op.cc

* Update lstm_op.cc

* add save kernel

* add save_sr_kernel

* remove original save_op

* add save gpu kernel

* remove combine kernel

* add port.h include

* add save selected rows test

* remove useless kernel.h

* fix init()

* delete test_device_context

* replace CPUDeviceContext with CPUContext

* fix test_scalar

* remove dot_op.cc

* fix compile

* Add bf16 support for save and load ops

* Add bf16 test condition

* Add matmul and chagne fluid.io to paddle.static

* Reduce the test duration

* Support converting the model from fp32 to fp16

* Incorporate cudnn_lstm into LSTM api.
test=develop

* Make coalesce_tensor support alignment optionally.
test=develop

* Reorganize RNN apis. test=develop

* Fix cudnn rnn layout conversion.
test=develop

* Add sequence_length support for RNN cudnn implement.
Add optional init_h and init_c gradient for cudnn_lstm_op.
test=develop

* Use create_parameter for rnn cudnn impl.
test=develop

* Move `self._flat_weight = self.create_parameter()` in RNNBase to main_program.
test=develop

* Update RNN api unittest to use set_device.
test=develop

* Fix set_place for unit tests of RNN apis.
test=develop

* Fix use_align in coalesce_tensor_op.
test=develop

* Adjust RNN apis arguments according to comments.
test=develop

* Polish documents for SimpleRNN apis.
test=develop

* Refine random seed in cudnn_lstm_op.
Expose rnn params from sublayers to RNN.
test=develop

* Fix RNN saving for jit.save.
Refine cudnn_lstm dropout behavior.
test=develop

* Fix doc of GRU. test=develop

* Use ShareDataWith to avoid copying for cudnn_lstm_op test.
test=develop

* Remove updates on cudnn_lstm temporarily.
test=develop

* Use ShareDataWith to avoid copying for cudnn_lstm_op test.
test=develop

* Refine random seed in cudnn_lstm_op.
test=develop

* Fix test_lstm by adjust ConcreteProgram buffer getter.
test=develop

* Use create_parameter instead of create_var for rnn._flat_weight for static graph usage.
test=develop

* Remove W input for cudnn_lstm to pass unused_var_check.
test=develop

* Add test_predict for RNN unit tests coverage.
test=develop

* Fix code style of rnn.
test=develop

* Fix F.rnn usage in rnn.py.
test=develop

* save InferVarType changes, test=develop

* remove code comments, test=develop

* tweak code, test=develop

* fix compilation warning, update merge_ids_op split_ids_op to new interface, test=develop

* modify fused_bn_activation_op, test=develop

* fix error of fused_bn_activation_op, test=develop

* fix PADDLE_ENFORCE and unittest coverage issue, test=develop

* tweak PADDLE_ENFORCE messages, test=develop

* improve unittest coverage, test=develop

* add StaticGraphInferVarType class, test=develop

* rebase develop branch, test=develop

* fix unittest error, test=develop

* remove comments, test=develop

* improve unittest coverage, test=develop

* imporve error message and imporve unittest coverage, test=develop

* upgrade InferVarType API, test=develop

* tweak pyfunc error message, test=develop

* fix compilation conflict - save_combine_op, test=develop

* support weight quantization in post_training_quanzitaion, test=develop
* add test for weight quantization, test=develop

* polish infer shape registry, test=develop

* modify some operators registry, test=develop

Add IndicateVarDataType interface to block tensor is not initialized problem in OP GetExceptedKernelType (#20044)

* add indicate_var_data_type inferface, test=develop

* add unittests & polish error message, test=develop

* remove needless include, test=develop

* extract public function & polish message, test=develop

* delete empty var check, test=develop

* change data_type to pointer parameter, test=develop

* polish details, test=develop

test=develop

test=develop

test=develop

test=develop

Fix code to support cpplint syntax check

test=develop